There are several types of electrode, in particular sintered and non-sintered electrodes, also called pasted or plasticized electrodes. The electrodes most widely used today are of the non-sintered type. Compared with other electrodes, a non-sintered electrode contains a greater quantity of active material, its volume specific capacity is thus increased and its production cost lower.
A non-sintered electrode consists of a support, serving as current collector, to which is applied a paste containing the active material and a binder, to which a conductive material is most often added. It is usually made by applying the paste in a porous three-dimensional conductive support such as a felt or a foam, made of metal or carbon. For reasons of cost, there is now a move towards the use of two-dimensional conductive supports. The known binders used to produce an electrode with a three-dimensional support prove unsuitable for a two-dimensional support.
By way of example, patent application EP 0 750 358 describes a non-sintered nickel electrode having a support comprising a corrugated metal sheet in which teeth have been formed in order to bind a microscopically rough layer. A paste comprising carboxymethylcellulose (CMC) and a styrene/butadiene (SBR) copolymer is applied to the layer. In that case it was necessary to use means other than the binder to ensure the mechanical strength of the electrode,
Also known is German patent application DE 19 709 107 which describes a nickel/metal hydride storage cell including an electrode formed from a paste applied to a substrate. The paste contains an acrylate binder having ester groups with 6 to 15 carbon atoms.